1. Field of the Invention
The invention generally relates to hydroxy alkyl amide analogs of ceramic and their use in the treatment of pathological conditions or disorders caused by abnormal cell growth, inflammatory processes, virus proliferation and processes involving aberrant protein kinase Cxcex6 (PKCxcex6) activity. The invention also relates to the use of hydroxy alkyl amide analogs of ceramic for analysis and diagnostic evaluation of 1) the enzyme PKCxcex6 and 2) programmed cell death (apoptosis), both in vitro and in vivo.
2. Background of the Invention
Sphingosine and its N-acylated derivative, ceramic (FIG. 1) are important lipid second messengers for regulation of cell growth and apoptosis (programmed cell death), as well as functioning as entry substrates for the generation of phospho-and glycosphingolipids. In particluar, apoptosis is known to be induced by elevation of endogenous ceramic or sphingosine (Ariga et al. 1998; Hannun and Linardic, 1993). Occasionally, cell growth and apoptosis share intracellular signal transduction by common protein kinase cascades. It is well known that apoptosis causes the death of half of the mitotic neuronal or glial cells during early periods of nervous system development (Mangoura and Dawson, 1998). Furthermore, spontaneous regression of astrocytoma tumors in young children has been correlated with an apoptotic process in rapidly dividing cells (Schwab, 1999).
Cerarnide specifically activates a protein kinase (ceramic activated protein kinase) and a phosphatase (ceramic activated phosphatase), both of which are known to participate in apoptotic or mitogenic signal transduction pathways (Ariga et al., 1998; Hannun and Linardic, 1993). Recently, a second protein kinase, protein kinase C zeta (PKCxcex6), has been reported to be regulated by ceramic and to constitute an important switch for mitosis versus apoptosis (Muller et al., 1995). Interestingly, in in vitro assays, it has been shown that the regulation is dependent on the effector concentration, in that PKCxcex6 appears to be activated at low concentrations of ceramic and inhibited at high concentrations of ceramic.
Structural analogues of ceramic are expected to specifically target sphingolipid-binding enzymes by acting as potential inhibitors or allosteric effectors. Ceramic analogues which are currently commercially available however, function only either as inhibitors of glycosphingolipid biosynthesis or ceramic degradation, in both cases giving rise to an elevation of endogenous ceramic. Two out of six enzymes critical for ceramic metabolism have been reported to be inhibited by structural analogues of ceramic. D-threo-1-phenyl-2-decanoylamino-3-morpholino-1-propanol (d-threo-PDMP) and related derivatives are known to inhibit glycosyl transferase (GT) whereas d-erythro-2-(N-myristoylamino)-1-phenyl-1-propanol (d-erythro-MAPP) and N-oleoyl ethanolamine (NOE) are used for inhibition of ceramidase (Abe et al., 1995; Arora and Radin, 1972; Bielawska et al., 1996). PDMP has been suggested for treatment of cancer by elevation of endogenous ceramic (see, for example, U.S. Pat. Nos. 5,952,370 and 5,041,441 to Shayman et al.). However, it has been reported that this ceramic analogue has detrimental side effects on the appearance and morphology of cultured neuroblastoma cells, and that it elevates ceramic in resting but not in rapidly dividing cells (Bieberich et al., 1999). Furthermore, a direct binding to distinct protein kinases involved in the regulation of apoptosis (e.g. PKCxcex6) has not been demonstrated.
Activity of PKCxcex6 has been implicated in: several types of cancer (e.g. colon, rectal, prostate, leukemia, etc.) (Hochegger et al., 1999; Powell et al., 1996; and Ways et al., 1994); infection by and proliferation of several types of viruses (e.g. Sendai, parainfluenza, HIV, etc.), (De et al., 1995; and Folgueira et al., 1996; Huntley et al., 1997); cell signaling in inflammatory processes (Jordan et al. 1996; MacDonald et al., 1999); and proliferation of epidermal and airway smooth muscle cells (Mani et al, 1999; Carlin et al, 1999; Das et al., 2000). In addition, aberrant activity of PKCxcex6 has also been implicated in the etiology of Alzheimer""s disease (Moore et al, 1998). The involvement of PKCxcex6 in these processes suggests that modulation of this enzyme may provide a means of treating related disease conditions.
It would be highly desirable to have available novel analogues of ceramic with high binding specificity for protein kinases (e.g. PKCxcex6) that are involved in the regulation of cell growth, differentiation, and apoptosis. It would be highly desirable to have available methods for administering such compounds in order to ameliorate disease conditions associated with regulation of cell growth, differentiation, and apoptosis. It would be highly desirable to have available compounds and methods of administering compounds which induce apoptosis specifically in rapidly dividing cells.
The present invention provides novel hydroxy alkyl amide compounds depicted in Formula I which are analogs of ceramic. The invention also provides methods of use for hydroxy alkyl amide compounds (depicted in Formula I and Formula II) which are analogs of ceramic to treat diseases associated with abnormal cell proliferation, inflammation and viral infection. The invention also provides methods for modulating the activity of the enzyme protein kinase Cxcex6 (PKCxcex6). The invention further provides methods for inducing apoptosis in cells both in vivo and in vitro.